1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1998 Doug Rabson 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd June 16, 1998 32.Dt DEVICE_ADD_CHILD 9 33.Os 34.Sh NAME 35.Nm device_add_child , 36.Nm device_add_child_ordered 37.Nd "add a new device as a child of an existing device" 38.Sh SYNOPSIS 39.In sys/param.h 40.In sys/bus.h 41.Ft device_t 42.Fn device_add_child "device_t dev" "const char *name" "int unit" 43.Ft device_t 44.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit" 45.Sh DESCRIPTION 46Create a new child device of 47.Fa dev . 48The 49.Fa name 50and 51.Fa unit 52arguments specify the name and unit number of the device. 53If the name is unknown then the caller should pass 54.Dv NULL . 55If the unit is unknown then the caller should pass 56.Dv -1 57and the system will choose the next available unit number. 58.Pp 59The name of the device is used to determine which drivers might be 60appropriate for the device. If a name is specified then only drivers 61of that name are probed. If no name is given then all drivers for the 62owning bus are probed. 63.Pp 64This allows busses which can uniquely identify device instances (such 65as PCI) to allow each driver to check each device instance for a 66match. For busses which rely on supplied probe hints where only one 67driver can have a change of probing the device, the driver name should 68specified as the device name. 69.Pp 70Normally unit numbers will be chosen automatically by the system and a 71unit number of 72.Dv -1 73should be given. 74When a specific unit number is desired (e.g. for wiring a particular 75piece of hardware to a pre-configured unit number), that unit should 76be passed. If the specified unit number is already allocated, a new 77unit will be allocated and a diagnostic message printed. 78.Pp 79If the devices attached to a bus must be probed in a specific order 80(e.g. for the ISA bus some devices are sensitive to failed probe attempts 81of unrelated drivers and therefore must be probed first), 82the 83.Fa order 84argument of 85.Xr device_add_child_ordered 9 86should be used to specify a partial ordering. 87The new device will be added before any existing device with a greater 88order. 89If 90.Xr device_add_child 9 91is used, then the new child will be added as if its order was zero. 92.Sh RETURN VALUES 93The new device if successful, NULL otherwise. 94.Sh SEE ALSO 95.Xr device 9 96.Sh AUTHORS 97This man page was written by 98.An Doug Rabson . 99